1. Field of the Invention
The present invention relates to a fuel supply system of an outboard motor for supplying a fuel stored in a fuel tank to an intake port of an engine.
2. Description of the Related Art
An outboard motor often used in a small craft is generally provided with a fuel supply system for supplying an intake port of an engine of the outboard motor with a fuel stored in a fuel tank provided on a hull side.
In this fuel supply system, a vapor separator for separating the fuel such as gasoline sucked up from the fuel tank by a low-pressure fuel pump into gas and liquid to release fuel vapor into the atmosphere, a fuel cooler for cooling the fuel having passed through the vapor separator by cooling water (seawater), a high-pressure fuel pump for pumping the fuel having passed through the fuel cooler, a pressure regulator for adjusting pressure of the fuel, an injector for injecting the fuel whose pressure has been adjusted by the pressure regulator to the intake port of the engine, and so on are generally provided.
As a conventional fuel supply system of this type, for example, one in which a high-pressure fuel pump and a pressure regulator are integrally provided in a case of a vapor separator and a water jacket (fuel cooler) for cooling the fuel is also provided in the case of the vapor separator, whereby the piping of a fuel system is simplified (for example, refer to Patent Document 1), and the like are publicly known.
[Patent Document 1] Japanese Laid-open Patent Publication No. 10-218089
However, in the above-described conventional fuel supply system, since the vapor separator and the high-pressure fuel pump are integrally provided, the size of the vapor separator becomes large for an outboard motor, which has a problem of difficulty in making the outboard motor compact.
Therefore, to solve this problem, there has also been proposed a fuel supply system using what is called an in-line high-pressure fuel pump connected in the middle of a fuel pipe. However, the fuel supply system of this type has a problem that it is difficult to completely draw off a fuel in the fuel pipe or the like between a vapor separator and the high-pressure fuel pump at the time of tilt-up and this work takes a lot of trouble.